Heat oil & ghee in a pan over medium-high heat. When the oil is hot enough, add in the whole spices to the pan and let them crackle for few seconds until aromatic.
Add the onion paste and sauté for 5-6 minutes or until they are light brown loses the raw smell.
Add in the ginger-garlic paste and sauté for 2 minutes.
Now add the turmeric powder, red chilli powder, and mix well. Sauté for a minute.
Add the tomato puree and mix well again.
Let it cook for 10 minutes on medium-low heat. Stir occasionally.
Onion-Tomato masala is ready when there is no raw smell and oil starts oozing from the sides.
Now add in rajma masala, amchur masala & 1/2 tsp salt. Mix well. Add 1/2 cup water & cook for 2-3 minutes.
Add this onion tomato masala to the boiled rajma and mix well.
Adjust consistency with water. Add in the ground rajma paste prepared earlier. This step will make the curry very creamy.
Simmer & cook for 15 minutes on low heat stirring occasionally.
Finally add 2 slit green chillies, crushed Kasuri methi & garam masala powder. Mix well & adjust if needed.
Cook for 3-4 minutes on medium heat.
Add chopped coriander leaves and stir well again.
Turn off the heat. The curry will thicken up at this stage. (Adjust the consistency to your liking.)
Garnish with coriander leaves, onion leaves, and serve hot with rice or roti.